confirmationservlet.java

java web services how to program

// Fig. 11.25: ConfirmationServlet.java
// JAXMServlet that receives messages from BuyerProvider.
package com.deitel.jws1.jaxm.bookbuyer.receiver;

// Java core packages
import java.sql.*;
import java.io.*;
import java.util.*;

// Java extension packages
import javax.xml.messaging.*;
import javax.xml.soap.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class ConfirmationServlet extends JAXMServlet
   implements OnewayListener {

   private ProviderConnection buyerProvider;
   private Connection connection; // connection to database

   // setup connection to message provider
   public void init( ServletConfig servletConfig ) 
      throws ServletException 
   {
      super.init( servletConfig );

      // establish connection to provider
      try {
         ProviderConnectionFactory providerFactory = 
            ProviderConnectionFactory.newInstance();
         buyerProvider = providerFactory.createConnection();

         // obtain URL of properties file
         java.net.URL propertyURL = getClass().getResource( 
            "bookStock.properties" );

         // load properties file
         Properties databaseProperties = new Properties();
         databaseProperties.load( new FileInputStream( 
            propertyURL.getPath() ) );

         // load JDBC driver
         Class.forName( databaseProperties.getProperty( 
            "jdbcDriver" ) );

         // establish database connection
         connection = DriverManager.getConnection(
            databaseProperties.getProperty( "databaseURI" ) );
      } 

      // handle exception in provider connection
      catch ( JAXMException jaxmException ) {
         throw new ServletException( jaxmException.getMessage() +
            "\nUnable to connect to provider." );
      }

      // handle exception if database driver does not exist
      catch ( ClassNotFoundException classNotFoundException ) {
         throw new ServletException( 
            classNotFoundException.getMessage() +
            "\nUnable to load database driver." );
      }

      // handle exception in making Connection
      catch ( SQLException sqlException ) {
         throw new ServletException( sqlException.getMessage() +
            "\nUnable to make database connection." );
      }

      // handle exception in loading properties file
      catch ( IOException ioException ) {
         throw new ServletException( ioException.getMessage() +
            "\nUnable to load bookStock.properties." );
      }

   } // end method init

   // invoked upon receiving message
   public void onMessage( SOAPMessage message )
   {
      // determine whether order was successful
      try {

         // obtain ISBN, Quantity and Price attachments
         Iterator attachments = message.getAttachments();
         AttachmentPart isbnAttachment = 
            ( AttachmentPart ) attachments.next();
         AttachmentPart quantityAttachment = 
            ( AttachmentPart ) attachments.next();
         AttachmentPart priceAttachment = 
            ( AttachmentPart ) attachments.next();

         // obtain ISBN, Quantity and Price from attachments
         String isbn = ( String ) isbnAttachment.getContent();
         Integer quantity = new Integer( 
            ( String ) quantityAttachment.getContent() );
         Double price = new Double ( 
            ( String ) priceAttachment.getContent() );

         // ensure book availability
         if ( price.doubleValue() < 0 ) {
            System.err.println( isbn + " is unavailable" );
            return;
         }

         // SQL query to database
         Statement statement = connection.createStatement( 
            ResultSet.TYPE_SCROLL_INSENSITIVE,
            ResultSet.CONCUR_READ_ONLY );

         // make query to determine number of available books
         ResultSet resultSet = statement.executeQuery( "SELECT" +
            " quantity FROM books WHERE isbn = " + isbn );

         // update BookStock1 databases content
         if ( resultSet != null ) {
            resultSet.next();
            int newQuantity = resultSet.getInt( "quantity" ) + 
               quantity.intValue();

            // update quantity of books in database 
            statement.execute( "UPDATE books SET quantity = " + 
               newQuantity + " WHERE isbn = " + isbn );

            // place order (ibsn, quantity and price) in database
            statement.execute( "INSERT INTO orders " +
               "( isbn, quantity, price ) VALUES ( '" + isbn + 
               "' , '" + quantity + "' , '" + price.toString() + 
               "' )" );
         }

         statement.close();
      }

      // handle exception in accessing database
      catch ( SQLException sqlException ) {
         sqlException.printStackTrace();
      }

      // handle exception in parsing SOAP message
      catch ( JAXMException jaxmException ) {
         jaxmException.printStackTrace();
      }

      // handle exception in obtaining message attachments
      catch ( SOAPException soapException ) {
         soapException.printStackTrace();
      }

   } // end method onMessage

} // end class ConfirmationServlet